An important device of Provox control system is a unit known as NIU which functions as software/hardware interface to connect engineering computer to Provox intranet. NIU is an obsolete device and the spare parts required for its maintenance are unavailable. Due to hardware issues in NIU, it was not possible for instrumentation experts to diagnose and troubleshoot the potential faults in DCS control system. Having provided the HDL as well as license files and software, installation and commissioning of the device was successfully fullfilled by Paya Control Afzar’s expertise and then DCS system was revived to normal operation.